Laminar flow may comprise, for example but without limitation, a flow of air in a boundary layer over a contour of parts of an aircraft such as wings, fuselage, and the like. The term boundary layer refers to a thin layer of air that forms next to a surface of an aircraft in motion, wherein a velocity of the air relative to the aircraft changes rapidly from zero at the surface to a local external velocity. The air flow within the boundary layer can be smooth as in a laminar state, or chaotic as in a turbulent state, or a transitional state wherein the air flow is intermittently laminar or turbulent. The transition from laminar to turbulent state of the boundary layer is induced by either gradual growth of natural flow instability or an abrupt disturbance caused by surface protuberances. From a perspective of minimizing viscous drag on the aircraft moving through air, it is desirable to establish and prolong as much as possible a laminar state of the boundary layer on a surface of the aircraft. Controlling growth of natural instability in a laminar boundary layer as well as minimizing surface protuberances can prolong the laminar state of the boundary layer in order to minimize viscous drag on the aircraft.
A smooth surface of an aerodynamic body designed to prolong laminar boundary layer flow for reducing viscous drag may be called a laminar flow surface. A laminar flow aerodynamic surface may prolong (extend) laminar boundary layer flow by modifying a contour of the laminar flow aerodynamic surface. However, such contouring of the laminar flow aerodynamic surface may not always be possible due to structural constraints and possible adverse impacts on other components of aerodynamic drag.